The present invention relates to an apparatus for mounting a siphon tapping tube onto a converter vessel, and in particular, to one used in the connecting or disconnecting operation for mounting or dismounting a siphon tapping tube on or from the tap hole mounting part of a converter vessel.
The surface of the molten metal or alloy in a converter has a floating cover of slag. When the converter is tilted to tap the molten metal from the tap hole, and in particular at the end of tapping, the slag tends to run out together with the molten metal. As it is not desirable to allow the slag to mix in the molten metal, a variety of schemes have been tried. Such contrivances include a separate tapping apparatus which is described in U.S. Pat. No. 4,274,622. This apparatus uses the siphon tapping method, and a bent tap passage is provided in a plane which crosses the horizontal plane when the converter is in its tapping position. The tap passage is so shaped and arranged that the static pressure of that portion of the molten metal which has remained in the tap passage after the molten bath has been discharged is kept in balance with the static pressure of the slag following the flow of the molten metal to prevent the discharge of slag out of the tap passage.
The above-mentioned bent tap passage is the siphon type converter tap hole pipe, and this tap hole pipe is mounted on the tap hole pipe mounting part of the converter. The siphon type tap hole pipe is composed of a steel tube with an inner refractory lining. As the refractory lining is worn down by the passage of molten metal, it is necessary to frequently dismount and mount the tap hole pipe from and on the converter vessel for repairs. The portions of the converter near the tap hole experience secular change due to, for example, heat load of the molten metal. This also applies to the repaired siphon tapping tube, resulting in dimensional errors between two objects. Furthermore, the converter vessel can be rotated clockwise and counterclockwise through an angle of 360.degree. by the converter tilting unit, and its positioning accuracy is such that a small error is always present in the halt position of the center of the tap hole mounting part of the vessel. Accordingly, it is necessary to align the siphon tapping tube and the tap hole mounting part of the converter whenever the tap hole pipe is to be mounted on the converter. In addition, since the dismounting and mounting operations of the siphon tapping tube must be completed within a limited time in converter operation, the accuracy and rapidness of the operations are desired.
The siphon tapping tube and the tap hole mounting part are generally arranged to be connected by their respective flanges and bolts and nuts. However, this connection poses problems such that many man-hours are required to align every bolt holes of the flanges, and that many man-hours are required to tighten all bolts and nuts. These problems of man-hour requirement resulting from the use of bolts and nuts are also experienced when the siphon tapping tube is dismounted from the converter vessel.
Accordingly, it is indispensible to quickly carry out the above-mentioned mounting and dismounting operations, and to assure easy execution of the operations, for the practical application to the commercial converters. Such an arrangement has been realized by the connecting system of the siphon tapping tube proposed in Japanese utility model provisional pub. No. SHO-57-154750. The system reduces the work load of the mounting and dismounting of the siphon tapping tube onto and from the converter by means of a hoist or a crane in front of the converter.
However, even if the above-mentioned connecting system is used, it still requires about 45-60 minutes to perform mounting and dismounting. During the time, the converter operation must be interrupted. Hence much more quickening of the operation is required. Some operations such as mounting or dismounting the siphon tapping tube, being a heavy object, on or from the converter vessel by means of a crane in front of the converter having inherent problems of lower efficiency and safety. Improvement of such points are also required.